1. Field of the Invention
The present invention relates to an electrical connector for electrically connecting a central processing unit (CPU) with a printed circuit board (PCB), and particularly to an electrical connector with improved terminals for soldering to the PCB via solder balls.
2. Description of Related Art
Ball grid array (BGA) sockets are widely used in personal computer (PC) systems to electrically connect CPUs with PCBs. A BGA socket comprises a multiplicity of terminals arranged in a rectangular array, with each terminal having a solder ball attached thereon.
Conventional soldering procedure is: the solder ball is positioned on the terminal, the solder ball is heated and melted, and the terminal is thereby soldered and electrically connected with the PCB. This conventional procedure is disclosed in xe2x80x9cBGA sockets: a dendritic solutionxe2x80x9d (P460xcx9c466, 1996 IEEE 46th electronic Components and Technology Conference).
U.S. Pat. No. 5,997,317, Taiwan Patent No. 392975 and China Pat. No. 98252275.4 all disclose an electrical terminal of an electrical connector comprising a contact portion and a solder portion substantially perpendicular to the solder portion. A dimple is defined in a center of a bottom of the solder portion. A width of the dimple is less than a width of the solder portion. A solder ball is held in the dimple.
Conventionally, the width of the dimple is relatively small. Therefore, it is difficult to precisely position the solder ball in the dimple. In addition, the melted solder ball is prone to wick along the terminal of the electrical connector when the solder ball is soldered to the PCB.
In view of the above, a new electrical connector that overcomes the above-mentioned disadvantages is desired.
Accordingly, an object of the present invention is to provide an electrical connector for electrically connecting a CPU with a PCB, whereby the electrical connector can ensure that solder balls are precisely located on terminals of the electrical connector to prevent the melted solder balls from wicking along the terminals.
To achieve the above-mentioned object, an electrical connector for electrically connecting a CPU with a PCB is provided by the present invention. In a preferred embodiment, the electrical connector comprises a base, and a cover slidably engaged on the base. The base comprises a body, and a multiplicity of holes defined through the body. The holes are arranged in a rectangular array, and retain a multiplicity of terminals therein. Each terminal comprises a solder portion adapted to receive a solder ball fused thereon. A curved dimple is defined in a middle of a bottom of the solder portion. A largest cross-sectional area of the dimple is slightly less than an area of the solder portion.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: